Test tightly coiled, subquadrate, test with compressed chambers. Final chamber much compressed, elongate, forms about half of the test and typically overhangs the earlier chambers. Aperture umbilical; thin elongate lip along part of aperture with squared-of ends. The test wall is coarsely and symmetrically cancellate, spinose.

Test medium sized, lobulate, trilobate with 3-3½ chambers in final whorl, increasing moderately in size. The ultimate chamber forms up to ½ of the test. Intercameral sutures depressed, straight to slightly curved on umbilical and spiral sides of the test. Umbilicus narrow, deep, often covered by a well developed apertural lip. Aperture umbilical, slightly asymmetrical towards an extraumbilical direction. The test walls strongly cancellate, spinose.

Test small (<250µm) low trochospiral, tightly coiled with 3½ chambers in final whorl Aperture umbilical with a thin lip. The ultimate chamber is equal to, or slightly smaller than the penultimate one. The wall is weakly cancellate and spinose. The spines are set at the junctures of the cancellate ridges. The umbilicus is small and nearly closed by the tight coiling.

Taxonomy

Citation: Subbotina Brotzen and Pozaryska, 1961Rank: GenusType species: Globigerinatriloculinoides Plummer, 1926, emended.Taxonomic discussion: Most species included in this genus were originally described as Globigerina. However, they differ in having a sacculifer or sacculifer/ruber-type wall (with the possible exceptions of S. roesnaesensis n. sp. and S. crociapertura, which show transition to the bulloides-type wall). Subbotina is distinguished from Globoturborotalita by its larger size, generally more embracing chambers and more asymmetrical aperture. Subbotina was emended to include the spinose wall texture by Olsson and others (1999). In some Eocene species extensive, heavy gametogenic calcification is observed. This apparently reflects a greater range of adaptation to the water column in the Eocene although isotope data indicates that most species were thermocline dwelling forms. [Olsson et al. 2006]

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.They are being edited as the site is developed and comments on them are especially welcome.

Description

Diagnostic characters: Low trochospiral, tripartite test with 10-12 chambers, with 3-4 rapidly inflating, globular chambers in ultimate whorl. Aperture interiomarginal, umbilical to slightly extraumbilical in most species, a low arch. Apertural lip varies from narrow to fairly broad with a distinct apparatus extending over umbilicus. Umbilicus small and nearly closed by tight coiling. Wall cancellate and spinose; spines set at juncture of the cancellate ridges with or without spine collars. Cancellate texture varies from weak to very strong and from moderate to very coarse or distinctly honeycombed. [Olsson et al. 2006]

Biogeography and Palaeobiology

Phylogenetic relations: Subbotina evolved from Eoglobigerinaeobulloides in the lower part of Zone Pα. Globoturborotalita and Globigerina have their origin in the genus Subbotina. [Olsson et al. 2006]NB Alternatively Koutsoukos (2014) suggests origin from Praemurica.

Biostratigraphic distribution

Geological Range: Notes: Base of Zone Pα to the top of O6.Plummer, 1926. [Olsson et al. 2006]Last occurrence (top): at base of Aquitanian Stage (3% up, 23Ma, in Aquitanian stage). Data source: Total of range of species in this databaseFirst occurrence (base): near base of Danian Stage (7% up, 65.7Ma, in Danian stage). Data source: Total of range of species in this database